SPRINGFIELD, Ill. (AP) — The state board of education is bracing for a headache ahead of the annual release of schools' individual report cards, which will detail the plunge in the number of students who met or exceeded Illinois standards on statewide tests for the 2012-13 school year.

The board said the dramatic drop in scores on the Illinois Standards Achievement test given to third- through eighth-graders wasn't caused by a change in teaching or student performance. Rather, it was the result of the board's decision to toughen the grading scale to better prepare for tougher, national standards being adopted next year.

Under the old scoring method, students would have made gains, according to the board.

Composite scores released earlier this year showed the dramatic drops. The report cards being released Thursday will show test results of individual public schools.

The change has been several years in the making as Illinois, like most states, prepares to adopt more rigorous national testing standards known as Common Core Standards in 2014-15.

Christopher Koch, the state superintendent of education, said the board spotted a "disconnect" between the testing standards applied to elementary students and those used for high school students. He said the board decided to make changes now to lessen the blow of adopting Common Core.

Along with changing the grading scale, some Common Core questions were phased into last spring's test.

Koch said it has been a difficult year preparing districts, because the drop in test scores leaves the impression that more students than ever are failing.

Adding to the communications problem is that the state has not received a waiver from federal No Child Left Behind requirements. The law requires schools to make "adequate yearly progress," or gains on the percentage of students meeting standards every year on state tests.

Because of the change on the ISAT grading scale, only 62 of 863 districts met the NCLB progress benchmarks this year, compared to 152 making the mark last year. As a result, the board had to generate an entirely separate "report card" showing the high number of failing schools, which Koch said "further confused the public."

"It makes no sense at all, but there's nothing I can do about this," Koch told The Associated Press. "What I can control is the things that we're doing."

Under the new scoring system, statewide averages show the overall percentage of elementary school students who met or exceeded the Illinois Standards Achievement Test standards for reading, math and science dropped from 82.1 percent in 2011-12 to 61.9 in 2012-13.

However, applying the new scoring standards retroactively would show that scores in all subjects went up from 2009 through 2013.

Page 2 of 2 - Several districts began preparing parents and students for the coming changes last spring.

Kyle Thompson, an assistant regional superintendent in eastern Illinois who was working in the downstate community of Chester at the time, said the district sent students home with flyers about the changes.

"We sent out charts to make things as simple as possible," he said.

In Elgin Area Unit District, Superintendent Joes Torres said he likened it to adjusting the body mass index scales overnight. All of a sudden, he told parents, some of them would be considered obese without gaining a pound.

"All of those nuances are difficult to explain in a sound bite," he told the AP. "I used the BMI, because I think people relate to that."

Despite the early efforts, Torres acknowledged that some families of the 40,000 district students are likely unaware of the changes.

Koch acknowledged that a number of parents could be getting the information for the first time this fall.

Jaime Wagoner, whose son Jackson is a fourth grader at Sherman Elementary, said she tries to "stay up" on school issues and moved to the central Illinois town because of its highly regarded district. But she said she doesn't recall ever being told about the new scores.

"If it was communicated it wasn't clear that these tests were going to be harder and this was the purpose of it," she said.

The annual report card being released to parents Thursday has added clearer details about students' academic progress from one year to the next, as well as information noting the scoring changes.

Still, Torres said, the comparison from last year to this year is in itself problematic.

"This should be considered ground zero," he said. "This (year's scores) should become the basis to evaluate next year's scores."